* [ASSERT_]MP_LOCK_HELD() was not properly handling the new token
t_count format.

* Rename and document the functions a bit better. Currently our
more expansive token test for (shared or exclusive) is not
a perfect test because we don't want to eat cpu time iterating
the thread's token array to check for shared tokens. So we just
check for a shared count.

Works well for assertions, wouldn't work very well for conditional
acquisition (of a shared token).